1. Technical Field
Various embodiments generally relate to semiconductor devices, and more particularly, to a technology for reducing the loading of global input/output lines.
2. Related Art
In general, a semiconductor memory device may include several tens of millions of memory cells for storing data. A semiconductor memory device may store or output data according to a command received from a central processing unit.
That is to say, data may be stored in memory cells that correspond with the addresses inputted from the central processing unit. This may occur when the central processing unit requests a write operation. The data stored in the memory cells corresponding to the addresses inputted from the central processing unit may then be outputted when the central processing unit requests a read operation.
In other words, the data inputted through data pads are inputted to memory cells through data input paths in the write operation. The data stored in memory cells are outputted to an exterior by way of data pads through data output paths.
Semiconductor memory devices may trend toward high speed operation and large capacity, and thus, the number of data consecutively inputted through one data pad is increasing.
In a semiconductor memory device, in particular, a DRAM, a data input/output bandwidth means the number of data which may be simultaneously read or written through addressing of one time.
By controlling the number of data to be inputted and outputted, according to a use of the DRAM, it is possible to perform an operation efficiently. The data input/output bandwidth may also mean the number of data input/output pads which are provided in the DRAM.
As the operation speed and the processing capacity of a semiconductor memory device increases, the semiconductor memory device includes a plurality of pads and a plurality of data input/output lines, and may input/output a plurality of data at a time.
According to the number of data which may be simultaneously processed by a semiconductor memory device in one read or write operation, X4, X8 and X16 input/output modes are used. In other words, the X4 input/output mode means a mode in which 4 data are simultaneously inputted and outputted in one read or write operation, and the X8 and X16 input/output modes mean modes in which 8 and 16 data are simultaneously inputted and outputted in one read or write operation, respectively.
In a conventional semiconductor memory device, a number of multiplexers for performing a X4 operation and a number of drivers for driving data regions with a DQ0 to DQ3 bandwidth and a DQ4 to DQ7 bandwidth are disposed in a Y-hole region. Therefore, the size of the Y-hole region increases due to the presence of the drivers for driving the data region with the DQ4 to DQ7 bandwidth and the multiplexers.